On 11 Oct 2001, Thomas Duffy wrote:
> I have setup a little (280G) xfs on RAID 10 (RAID 1 on RAID 0). This
> has 8 SCSI drives (4 per card).
>
> Everything seems to work fine, expect the RAID resync craaaawwwllllsss.
> It goes at the minimum of 100k/s which should take a few months to
> finish syncing :) It sometimes bumps up to 250 k/s, but never higher
> even with no system activity.
>
> First off, does anyone know of a way to bump the sync rate up? Could
> this be some sorta weirdness between XFS and MD that is causing the slow
> resync? On a simple RAID 1 setup (2 disks) w/ XFS on the device, the
> resync is as speedy as the SCSI card allows when there is no other I/O
> which is what I would expect from MD.
[snip]
echo N > /proc/sys/dev/raid/speed_limit_min
where N is how many KB per second you want the raid driver to attempt
to resync at. There is a speed_limit_max, which you'd think would be
the controlling factor, but I've several times seen what you describe,
and setting speed_limit_min to something like 25000 or 50000 greatly
decreases the resync time.
Scott
--
Scott Murray
SOMA Networks, Inc.
Toronto, Ontario
e-mail: scottm@xxxxxxxxxxxxxxxx
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